On Aug 10, 3:20 pm, Dragan Djuric <draga...@gmail.com> wrote: > For example: > > (defmacro creator [param] > `(defmacro created [p] `(the code...)) ;; note the nested quote... > how to resolve that? any examples?
Although I wouldn't cite my own code as a necessarily *good* or easy to understand example, I'll pimp it anyway as it is written and already on the net... http://github.com/JonathanSmith/CRIB/blob/89a3f4d9c797ef6f4e4f456001ff6a4c5c050064/api_builder.clj A macro is exactly the same as a function, except it has special evaluation rules. You'll notice that in what I posted, I only use defmacro once, everything else is a function that returns a list (I've found that this gives me extra flexibility later on when I want to continue extending the macro-metaphor... (or if I happen to want to do runtime definition of certain things, I can swap out the macro for a function call and an 'eval')). You'll also notice that syntax quote qualifies every symbol that it is passed. Your particular example wouldn't work, because you can't define a name- space qualified symbol. There are two ways that you could circumvent this. 1.) use regular old list (list 'defmacro 'created ['p] `(code ...)) 2a.) Escape and quote certain things: `(defmacro ~'created [p#] `(code goes here..)) or 2b.) `(defmacro ~'created [p#] ~(fn-that-returns-your-code p# and probably some args and stuff)) or 2c.) (let [fn-that-generates-expansion (code-to-generate-a-fn-that-generates-an-expansion)] `(defmacro ~'created [p#] (~fn-that-generates-expansion p#))) You don't actually need to use nested backquote* (For anything**, AFAIK), I tend to avoid it because I think it makes the code fairly unreadable (yes, more unreadable than what I posted). I normally use a helper function and pass the arguments (similar to a foo and foo-1 function when doing recursion). --------------------- * backquote == syntaxquote ** I think I used nested backquotes one time in common lisp for something, but I can't remember *why* it was necessary, in particular. I think it is the case where you want to pass a symbol from one macro- environment to the next, say generating a bunch of accessors... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
